Proposal: addition of array_find() and array_find_key() functions

Hi

As with the array_group thread:

What is the argument to put these functions in hard to update C, rather than PHP that is easy to download with Composer? "could be a nice addition" is not a compelling argument. Is it substantially faster? It is truly universally used? Does it correct some security concern?

I am not sure if "hard to update" is a argument that applies here: There
is only one reasonable implementation of array_find and thus once the
function is written it is exceedingly unlikely to need any updates. When
was the last time array_filter, which is likely the most similar
existing function, needed an update?

From the list you've given, "universally used" appears to be the most
fitting description. A programming language needs a reasonable standard
library and array_find() [1] is something that should pop up
reasonably often in "functional array processing". It's available in
various languages [2].

My only concern is that this either is another function that either
instead of working on any iterable, works on arrays and arrays only - or
a function that is inconsistent with the rest of the array_* functions.

See also the discussion here: https://externals.io/message/118896#118896

Best regards
Tim Düsterhus

[1] As well as array_any() and array_all().

[2]

JS:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find
Rust: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.find
Haskell:
https://hackage.haskell.org/package/base-4.18.0.0/docs/Data-List.html#v:find
C++: https://en.cppreference.com/w/cpp/algorithm/find

sounds like array_find could be implemented by just adding a new flag
for array_filter's $mode:
ARRAY_FILTER_STOP_ON_FIRST_MATCH
or some such?

array_find(): This function would allow developers to find the first element in
an array that satisfies a specific condition. The condition would be defined by a callback function.

This would actually be an alternative to a simple foreach() with an if() and a break. As your example implementation makes clear.

array_find() and array_find_key() would still do the same internally, but add a function call adding the overhead of pushing parameters to stack, switching the scope, passing return value back switch scope and pop from the callstack again. If parameters or return value are typed this adds even more overhead.

I don't think there is any optimisation possible when this is done in C.

To the proposer it probably feels that this is an array function currently missing, but instead it's probably better not to have array_find() because people might actually use it for larger datasets.

Although I acknowledge that it will reduce the number of lines of PHP code it doesn't actually reduce the mental capacity to read and maintain code. I find the simple elemental building blocks of loops, conditionals and expressions easier and more expressive. In my experience this is especially so for less experienced developers.

Then there is a problem of naming. array_search() and array_find(). To a new developer, how would they know which is which?

Also there is the missing array_find_value_and_key() method. Because why should we be limited to either matching the key OR the value?

Greetings, Casper

W dniu 2.06.2023 o 02:14, Casper Langemeijer pisze:

array_find(): This function would allow developers to find the first element in
an array that satisfies a specific condition. The condition would be defined by a callback function.
This would actually be an alternative to a simple foreach() with an if() and a break. As your example implementation makes clear.

array_find() and array_find_key() would still do the same internally, but add a function call adding the overhead of pushing parameters to stack, switching the scope, passing return value back switch scope and pop from the callstack again. If parameters or return value are typed this adds even more overhead.

I don't think there is any optimisation possible when this is done in C.

To the proposer it probably feels that this is an array function currently missing, but instead it's probably better not to have array_find() because people might actually use it for larger datasets.

Although I acknowledge that it will reduce the number of lines of PHP code it doesn't actually reduce the mental capacity to read and maintain code. I find the simple elemental building blocks of loops, conditionals and expressions easier and more expressive. In my experience this is especially so for less experienced developers.

Then there is a problem of naming. array_search() and array_find(). To a new developer, how would they know which is which?

Also there is the missing array_find_value_and_key() method. Because why should we be limited to either matching the key OR the value?

Hi,

You are right about speed penalty for using those functions over simple
loops, however if we would stick to that point of view, we should
deprecate and remove array_filter, array_map, array_walk, array_u...

Proposed functions are not intended for developers working on large
arrays with speed constraints, but for simple usecases where (at least
for some people) readability will be improved by reducing 6 lines of
code to just 1.

"find" is consistent with names of the same function in other languages
as Tim has pointed in his email yesterday.

I leally do not see many uses for array_find_value_and_key, however - as
I you can see in my example implementations - condition is only checked
for the values of the array. We could have a nice family of
array_find_... functions including adding array_find_by_key and
array_find_key_by_key, array_find_by_value_and_key and
array_find_key_by_value_and_key... ;) or better discuss whether we
should pass both key and value to callback like below (order of the
arguments for the callback is to be discussed) or use flags like in
array_filter to decide what do we want to pass

function array_find(callable $callback, array $array)
{
    foreach ($array as $key => $value) {
        if (call_user_func($callback, $value, $key) === true) {
            return $row;
        }
    }
    return null;
}

vs

function array_find(callable $callback, array $array, int $mode = 0)
{
...
}

Best regards,
Janusz